Move FlagComputation to rustc_type_ir

Author: jackh726

compiler/rustc_middle/src/ty/pattern.rs

@@ -2,13 +2,34 @@ use std::fmt;
 
 use rustc_data_structures::intern::Interned;
 use rustc_macros::{HashStable, TyDecodable, TyEncodable, TypeFoldable, TypeVisitable};
+use rustc_type_ir::Flags;
 
+use super::flags::FlagComputation;
 use crate::ty;
 
 #[derive(Copy, Clone, PartialEq, Eq, Hash, HashStable)]
 #[rustc_pass_by_value]
 pub struct Pattern<'tcx>(pub Interned<'tcx, PatternKind<'tcx>>);
 
+impl<'tcx> Flags for Pattern<'tcx> {
+    fn flags(&self) -> rustc_type_ir::TypeFlags {
+        match &**self {
+            ty::PatternKind::Range { start, end } => {
+                FlagComputation::for_const_kind(&start.kind()).flags
+                    | FlagComputation::for_const_kind(&end.kind()).flags
+            }
+        }
+    }
+
+    fn outer_exclusive_binder(&self) -> rustc_type_ir::DebruijnIndex {
+        match &**self {
+            ty::PatternKind::Range { start, end } => {
+                start.outer_exclusive_binder().max(end.outer_exclusive_binder())
+            }
+        }
+    }
+}
+
 impl<'tcx> std::ops::Deref for Pattern<'tcx> {
     type Target = PatternKind<'tcx>;